This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Many viruses use molecular motors to package the nucleic acid into capsids. The viral packaging motor is ahighly robust and efficient molecular machinery driven by the adenosine triphosphate (ATP) hydrolysis. The high-resolution structure of the packaging motor was solved for the bacteriophage phi29 and phi22 by means of X-ray crystallography and cryo-electron microscopy. Due to the complexity of its structure, however, the dynamic behavior of the packaging motor still remains elusive. Understanding the dynamic mechanism of the packaging motor is essential to provide new insights into the principles of molecular machinery. In this study, we will investigate the DNA dynamics in the packaging motor using coarse-grained and detailed atomistic simulations.